The clinical study of neuro-attenuated replication competent HSV-1 mutants deleted for gamma-34.5 and[unreadable] ICP6 and amplicon vectors has been limited by the inability to consistently produce vector stocks in[unreadable] adequate quantity and quality. The goal of Core B will be to provide program investigators with MGH2[unreadable] (gamma-34.5/ICP6 mutant) and amplicon viral stocks that are both high in titer and highly purified while[unreadable] Deing consistently produced according to vector specific protocols. Vector stocks produced in this manner[unreadable] will be characterized across all major quality control areas that make up lot release criteria of DNA viruses[unreadable] for clinical use. This approach will result in generation of pre-clinical data that will not be hampered by issues[unreadable] of bio-equivalency between vector stocks that are used for pre-clinical studies and those that may be used[unreadable] later in a clinical setting. The use of highly purified and characterized vector stocks will also allow program[unreadable] investigators to more completely understand the potential efficacy and mechanism of activity of vector[unreadable] delivery in the pre-clinical setting without the worry of spurious results that may result from the use of nonuniform[unreadable] vector stocks or vector stocks that are contaminated with wild type virus or high levels of defective[unreadable] particles, contaminating proteins, or host cell DNA.